Recently, China pointed out that as a result of its nuclear power generating program, Japan had “enough plutonium to make 5,500 nuclear warheads.” But nobody, not even China, stays up nights worrying about a nuclear attack from Nippon. To understand why nobody is worried about this, we must detour into technology and history. The reason Japan has so much plutonium is that it is an energy-poor country that relies on nuclear power and has few indigenous supplies of uranium to fuel it. Wishing to protect itself against supply chain risk, it decided to use nuclear waste – plutonium – as fuel. As the Japan Atomic Energy Commission put it: “...since Japan is poor in energy resources and reserves of uranium were considered to be finite, Japan has adopted, from the beginning of nuclear energy use, a nuclear fuel policy that uses plutonium separated from spent nuclear fuel.”
To make it impossible, or at a minimum, difficult for Tokyo to turn its 44.4-ton plutonium stockpile into infernal weapons, Japan refines it in Europe only to a reactor, not weapons-grade, and stores 35.8 tons of it in the United Kingdom and France, leaving only 8.6 tons in Japan for power generation use. Japan technically owns the material, but it is physically held overseas until it can be returned in a form ready for reactor use or otherwise managed.
All the same, given Japan’s advanced nuclear industry and technologically advanced space programs, there is little doubt that Tokyo is, as a practical matter, completely capable of building a nuclear arsenal in short order. “Chinese nuclear experts believe Japan could build nuclear weapons in less than 3 years.” Nor is Japan the only “latent nuclear” power. Germany, South Korea, and Taiwan could build one easily, with Canada, the Netherlands, Brazil, and Australia just a touch behind. Why are nations not staying up nights worried about the nuclear menace from Canada? Because it lacks a history of malicious intent. Each of these countries approached the nuclear weapons threshold as a byproduct of their general technological development, little caring about conquering the world.
By contrast, the Islamic Republic of Iran is developing nuclear weapons as an end in itself. Ironically, it was experience fighting other Muslims that convinced Tehran it must have a nuclear deterrent. If Canada never thought about conquering the world, the Middle East was a crucible where dictators thought about nothing else. “The 1980–88 Iran-Iraq War stands as the pivotal event for Iran's national security strategy, especially as it pertains to the country's controversial nuclear program.”
Iraq's use of chemical weapons against Iran and Baghdad's progress toward a nuclear capability added to the pressing need to develop a deterrent. In 1988, shortly after the war ended, Rafsanjani stated that “chemical bombs and biological weapons are the poor man's atomic bombs and can easily be produced. We should at least consider them for our defense.”
So in the late 1980s and 1990s, convinced of the advantages of having WMDs, Iran acquired key technology covertly, notably centrifuge designs and components from the A.Q. Khan network in Pakistan. Secret facilities were built: Natanz (uranium enrichment) and Arak (heavy-water reactor for potential plutonium path). By the early 2000s, Iran had a structured effort including uranium enrichment, weaponization studies, and missile delivery work. All these secret efforts have reportedly produced 440.9 kg of uranium enriched up to 60% (as of mid-June 2025, on the eve of Israeli-U.S. strikes) – less than 1% of the Japanese stockpile.
Less than 1%? So why are we worried? This highlights a key factor so often ignored in the media coverage of the issue of the danger of nuclear proliferation. It is not the possession of nuclear capability in itself that constitutes an international threat, but demonstrated hostile intent. The threat level depends overwhelmingly on who holds nuclear technology and what they intend to do with it — not the mere existence of the capability. It’s one thing for Canada to have nukes, another for Iran. Japan has had the technical ability to build nuclear weapons for decades. It has never demonstrated intent to do so. Its plutonium stockpile is a civilian legacy, kept under IAEA safeguards, and its security rests on the U.S. alliance. Iran, by contrast, has:
Openly called for Israel's elimination ("from the river to the sea" rhetoric and "wipe off the map" statements).
Built a network of terrorist proxies (Hezbollah, Hamas, Houthis, Iraqi militias) that attack U.S. forces, Israel, and Gulf states.
Launched direct ballistic missile and drone barrages at Israel, the GCC, and European possessions.
Funded and armed groups explicitly aiming at civilian targets, even in the Western hemisphere.
Maintained a nuclear program shrouded in secrecy with documented weaponization research (per IAEA and stolen archives).
Merely having nuclear capability is not an imminent threat. In the current conflict, two out of the three combatants are nuclear powers: the USA and Israel, yet ironically, no one worries either will nuke Iran. On the other hand, there is some debate over whether Iran would strike Israel or the USA even at the cost of their own destruction. Some feel that, given the Islamic Republic’s apocalyptic ideology, the first use of a nuclear weapon against the hated Jews is not impossible. But the mainstream consensus appears to be that the ayatollahs would employ nuclear weapons as blackmail, the way it currently uses the threat to block the Straits of Hormuz to wrest concessions, extort payments, or achieve impunity and thus dominate the region.
Alternatively, it could supply nukes, as it does drones and missiles to proxies, creating a “nuclear Hezbollah,” theoretically allowing it to menace other countries without taking direct responsibility. Nuclear weapons are, in a way, like ordinary guns. Nothing to worry about in the hands of law-abiding individuals but a deadly menace in the possession of a fanatic screaming “Death to America”.
This is why analysts who focus only on "number of warheads" or "enrichment levels" miss the point. A nuclear Japan or Germany would likely be stabilizing today. A nuclear Iran almost certainly would not. The regime's ideology, its use of proxies, and its stated goals matter far more than kilograms of weapons.
